Pseudicyema jinshoae, Furuya & Moritaki, 2022
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publication ID |
https://doi.org/ 10.12782/specdiv.27.181 |
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publication LSID |
lsid:zoobank.org:pub:03A070DC-A02C-4FF8-A00D-FD59C7614189 |
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persistent identifier |
https://treatment.plazi.org/id/7AAC579F-0307-42BC-9E97-655CC007C23E |
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taxon LSID |
lsid:zoobank.org:act:7AAC579F-0307-42BC-9E97-655CC007C23E |
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treatment provided by |
Felipe |
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scientific name |
Pseudicyema jinshoae |
| status |
sp. nov. |
Pseudicyema jinshoae sp. nov.
[New Japanese name: Jinsho-nihaichū] ( Figs 26 View Fig , 27 View Fig ; Tables 1–3)
Diagnosis. Small-sized dicyemid, body length reaching 1210 µm. Calotte cap-shaped. Vermiform stages with 30–35 peripheral cells: 4 propolar cells+4 metapolar cells+ 2 parapolar cells+20–25 trunk cells. Infusoriform embryos with 39 cells; refringent bodies solid; and 2 nuclei present in each urn cell.
Description. Nematogens ( Figs 26a, b View Fig , 27a, c, d View Fig ). Body length 800–1210 µm, width 38–50 µm; widest in region of parapolars; trunk width mostly uniform. Peripheral cell number 30–35 ( Table 2): 4 propolar cells+4 metapolar cells+2 parapolar cells+18–23 diapolar cells+2 uropolar cells. Calotte cap-shaped, rounded anteriorly; cilia about 4 µm long, oriented anteriorly. Propolar cells equal to or larger than metapolar cells, their nuclei equal to or smaller than metapolar cell nuclei. Propolar cells occupy anterior 50–60% of calotte length when viewed laterally ( Figs 26a, b View Fig , 27c, d View Fig ). Cytoplasm of propolar cells more darkly stained by hematoxylin than that of other peripheral cells ( Fig. 26a, b View Fig ). Axial cell cylindrical, rounded anteriorly, extending from middle of parapolar cells to base of propolar cells ( Figs 26a, b View Fig , 27c, d View Fig ). About 10 vermiform embryos present per axial cell of large individuals. Accessory nuclei seen in trunk peripheral cells.
Vermiform embryos ( Figs 26c View Fig , 27f, g View Fig ). Full-grown vermiform embryos length 73–97 µm, 15–20 µm in width. Peripheral cell number 30–35 ( Table 2); trunk cells arranged in opposed pairs. Anterior end of calotte rounded. Axial cell pointed anteriorly, extending to the base of propolar cells ( Figs 26c View Fig , 27g View Fig ). Axial cell of full-grown embryos with 2 agametes.
Rhombogens ( Figs 26d View Fig , 27e View Fig ). Body length 820–1260 µm, similar to that of nematogens, in length and 40–60 µm in width. Peripheral cell number typically 30–35 ( Table 2). Calotte, axial cell shape and anterior extent similar to nematogens. Maximum of 5 infusorigens present in the axial cell of each parent individual. About 40 infusoriform embryos present per axial cell of large individuals.
Infusorigens ( Figs 26e View Fig , 27h; n View Fig =10). Mature infusorigens medium-sized; composed of 4–9 (mode 5) external cells (oogonia and primary oocytes)+2, 3 (mode 2) internal cells (spermatogonia, primary spermatocytes, and secondary spermatocytes)+5–14 (mode 8) spermatozoa. Mean diameter of fertilized eggs 11.9 µm; that of spermatozoa 2.5 µm. Axial cell round or ovoid, diameter 12–14 µm.
Infusoriform embryos ( Figs 26f, g View Fig , 27i–k; n View Fig =20). Fullgrown embryos large, length 22.8±1.5 µm (mean±SD, excluding cilia); length–width–height ratio 1.0:0.87: 0.85; shape ovoid, pointed posteriorly; cilia at posterior end 7 µm long. Refringent bodies present, solid, occupying anterior 30–40% of embryo length when viewed laterally ( Figs 26g View Fig , 27k View Fig ). Cilia project from ventral internal cells into urn cavity ( Fig. 27k View Fig ). Capsule cells contain tiny granules ( Fig. 27k View Fig ). Mature embryos with 39 cells: 35 somatic+4 germinal cells. Somatic cells of several types present: external cells covering large part of anterior and lateral surfaces of embryo (2 enveloping cells); external cells with cilia on external surfaces (2 pairs of dorsal cells+1 median dorsal cell+2 dorsal caudal cells+2 lateral caudal cells+1 ventral caudal cell+ 2 lateral cells+2 posteroventral lateral cells); external cells with refringent bodies (2 apical cells); external cells without cilia (1 couvercle cell+2 anterior lateral cells+2 first ventral cells+2 second ventral cells+2 third ventral cells); internal cells with cilia (2 ventral internal cells); and internal cells without cilia (2 dorsal internal cells+2 capsule cells+4 urn cells). Each urn cell containing 2 nuclei and a germinal cell ( Fig. 27k View Fig ). All somatic nuclei pycnotic in mature infusoriform embryos.
Remarks. Pseudicyema jinshoae sp. nov. is the first species of the genus found in S. subtenuipes . It is very similar to P. anemophilum sp. nov., P. cappacephalum , P. cupulacephalum sp. nov. and P. daioense sp. nov. in the calotte shape and the number of infusoriform embryos ( Furuya 2009). However, P. jinshoae sp. nov. is distinguished from P. anemophilum sp. nov. by the anterior extent of adult vermiform stages (metapolar cells vs. propolar cells). Pseudicyema jinshoae sp. nov. differs from P. cappacephalum and P. cupulacephalum sp. nov. in the maximum number of infusorigens (5 vs. 3). In addition, P. jinshoae sp. nov. can be separated from P. daioense sp. nov. by the external shape of second ventral cells of infusoriform embryos (extended laterally vs. located ventrally).
Etymology. The species name “ jinshoae ” refers to name of the bottom trawl fishing boat “Jinsho-maru” which caught the host cephalopods.
Taxonomic summary. Type material: a syntype slide (NSMT-Me-69) collected on 25 June 2018; additional syntypes on slide series No. SS3864 (5 slides) in the author’s collection.
Type locality: off Kii-Nagashima (34°01′N, 136°40′E), Mie Prefecture, Honshu, the Kumano Sea, Japan, depth 160 m GoogleMaps .
Other materials examined: slide series No. SS3869 (5 slides) collected off Kii-Nagashima (34°01′N, 136°40′E), Mie Prefecture, Honshu, the Kumano Sea, Japan, depth 160 m, 25 June 2018, in the author’s collection GoogleMaps .
Host: symbiotype, Sepia subtenuipes Okutani and Horikawa, 1987 (Mollusca: Cephalopoda: Sepiida ), female (submature), 116 mm ML (NSMT-Mo-85911).
Collector of host: T. Moritaki.
Site : anterior ends (calottes) attach to surfaces of the renal appendages or inserted into crypts of the renal appendages within the renal sacs.
Prevalence: in 8 of 30 host specimens examined (26.7%).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.